﻿using System;
using System.IO; 
using System.Text;
using System.Data;
using System.Collections;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Globalization;
using System.Security.Cryptography;  


   /// <summary>
 /// MD5 的摘要说明。
 /// </summary>
 public class MD5
 {
  public MD5()
  {
   //
   //
  }
  public string MD5Encrypt(string pToEncrypt, string sKey)
  {
      DESCryptoServiceProvider des = new DESCryptoServiceProvider();
      byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
      des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
      des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
      MemoryStream ms = new MemoryStream();
      CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
      cs.Write(inputByteArray, 0, inputByteArray.Length);
      cs.FlushFinalBlock();
      StringBuilder ret = new StringBuilder();
      foreach (byte b in ms.ToArray())
      {
          ret.AppendFormat("{0:X2}", b);
      }
      ret.ToString();
      return ret.ToString();


  }

  ///MD5解密   
  public string MD5Decrypt(string pToDecrypt, string sKey)
  {
      DESCryptoServiceProvider des = new DESCryptoServiceProvider();

      byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
      for (int x = 0; x < pToDecrypt.Length / 2; x++)
      {
          int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
          inputByteArray[x] = (byte)i;
      }
      des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
      des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
      MemoryStream ms = new MemoryStream();
      CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
      cs.Write(inputByteArray, 0, inputByteArray.Length);
      cs.FlushFinalBlock();

      StringBuilder ret = new StringBuilder();

      return System.Text.Encoding.Default.GetString(ms.ToArray());
  }

  // 创建Key   
  public string GenerateKey()
  {
      DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create();
      return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
  }
  // 加密字符串   
  public string EncryptString(string sInputString, string sKey)
  {
      byte[] data = Encoding.UTF8.GetBytes(sInputString);
      DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
      DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
      DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
      ICryptoTransform desencrypt = DES.CreateEncryptor();
      byte[] result = desencrypt.TransformFinalBlock(data, 0, data.Length);
      return BitConverter.ToString(result);
  }
  // 解密字符串   
  public string DecryptString(string sInputString, string sKey)
  {
      string[] sInput = sInputString.Split("-".ToCharArray());
      byte[] data = new byte[sInput.Length];
      for (int i = 0; i < sInput.Length; i++)
      {
          data[i] = byte.Parse(sInput[i], NumberStyles.HexNumber);
      }
      DESCryptoServiceProvider DES = new DESCryptoServiceProvider();
      DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
      DES.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
      ICryptoTransform desencrypt = DES.CreateDecryptor();
      byte[] result = desencrypt.TransformFinalBlock(data, 0, data.Length);
      return Encoding.UTF8.GetString(result);
  }

 }

